Seasonal and diurnal soil respiration dynamics under different land management practices in the sub-tropical highland agroecology of Ethiopia

Abstract

The temporal dynamics of soil respiration change in response to different land management practices is not well documented. This study investigated the effects of soil bunds on the monthly and diurnal dynamics of soil respiration rates in the highlands of the Upper Blue Nile basin in Ethiopia. Six plots (with and without soil bunds, three replicates) were used for measurement of seasonal soil respiration, and eighteen plots were used for measurement of diurnal soil respiration. We collected seasonal variation data on a monthly basis from September 2020 to August 2021. Diurnal soil respiration data were collected four times daily (5 a.m., 11 a.m., 5 p.m., and 11 p.m.) for two weeks from 16-29 September 2021. A Wilcoxon signed-rank test showed that seasonal soil respiration rates differed signi cantly (p < 0.05) between plots with and without soil bunds in all seasons. In plots with soil bunds, seasonal soil respiration rates were lowest in February (1.89 ± 0.3 µmol CO 2 m − 2 s − 1 , mean ± SE) and highest in October (14.54 ± 0.5 µmol CO 2 m − 2 s − 1 ). Diurnal soil respiration rate was signi cantly (p < 0.05) higher at 11 a.m. than at other times, and was lowest at 5 a.m. Both soil temperature and moisture signi cantly affected seasonal variation in soil respiration. Diurnal variation in soil respiration was signi cantly affected by soil temperature but not by soil moisture. Further study is required to explore how differences in soil microorganisms between different land management practices affect soil respiration rates.